Re: 14-CURRENT Kernel Panic due to USB hub?

> On 30 Nov 2021, at 12:35, Hans Petter Selasky <hps@selasky.org> wrote:
> 
> On 11/30/21 13:22, Andrew Turner wrote:
>> I bisected the detached messages back to 601ee53858f6 [1]. If I revert this change I no longer see this on the console.
>> I am also unable to reproduce the panic with this change reverted. As the panic can be difficult to reproduce I am unsure if reverting this change is enough to fix it, or if it’s just making it less likely to be triggered.
>> Andrew
>> [1] https://cgit.freebsd.org/src/commit/?id=601ee53858f6
> 
> Hi,
> 
> Could you verify that you are not running out of kernel stack?

I can still trigger it after doubling the kernel stack size.

> 
> May this be due to some code in the .text segment which is not properly aligned?

I would expect to have seen the issue on other HW. The issue looks more like it’s memory corruption.

> 
> If you compile and load USB as modules, does the panic go away?

I am unable to trigger it after removing xhci from the kernel, and did get a panic after loading the xhci module.

The xhci controller is one that originated in Broadcom. Linux has a quirk for it to work around an erratum where attaching a USB 1 device followed by a USB 2 device the linker the latter will come up as USB 1. They reset the phy when anything less than USB 3 on a disconnect event. 

Andrew